Field
Exemplary embodiments relate to an electronic device, and, more particularly, to a supply modulator including a switched-mode power supplier and a transmitting device including the supply modulator.
Discussion
Battery power management is critical for certain electronic devices, such as mobile communication terminals. For such electronic devices, a high-efficiency radio frequency power amplifier may be provided to extend battery time.
As mobile communications technologies evolved from 2G to 3G and from 3G to 4G, high Peak-to-Average Power Ratio (PAPR) characteristic of an input signal has been achieved. However, the efficiency of a radio frequency power amplifier using a direct current (DC) source may decrease as the PAPR is increased. For example, such power amplifiers may have decreased power efficiency in a back-off power region. Therefore, there is an ongoing need for technologies for improving the power consumption efficiency of the radio frequency power amplifier having increased PAPR.
An Average Power Tracking (APT) method may be used to improve the decreased power efficiency in the back-off power region, where the APT method may track the average power of an input signal, control the supply voltage based on the tracking result, and amplify a radio signal by using the controlled supply voltage. However, the APT method does not track the envelope of the input signal in real time, and consequently, the radio frequency power amplifier that utilizes the APT method may still have a power loss.
An envelope tracking method may track the envelope of an input signal in real time, control the supply voltage based on the tracking result, and amplify a radio signal by using the controlled supply voltage. The envelop tracking method requires a supply modulator that modulates the supply voltage of a battery along the envelope of an input signal. Further, the supply modulator should have high power efficiency and a wide frequency bandwidth to cover envelope signals of various frequency bands.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.